What important discovery did researchers aboard the alvin make?

The correct answer will be hydrothermal vents  and deep-sea ecosystems.

Explanation:

Alvin stands is a deep-Sea Submersible which stands for  "Air-Launched Vehicle Investigation". This submersible is named after the engineer Allyn Vine of Woods Hole Oceanographic Institution (WHOI) who operates this submersible.  

Alvin is owned by the American navy today which has helped in scientific discoveries especially hydrothermal vents  (380° C) called  'black smokers' in East Pacific Rise in an expedition in 1979. This also helped in the understanding of deep-sea ecosystems which exists in dark conditions without sunlight.

Thus, hydrothermal vents  and deep-sea ecosystems are the correct answers.

the transfer of energy between two molecules spaced just nanometers apart plays a key role in many technologies, including photovoltaics, quantum information systems, lighting, and sensors, as well as in biophysics to measure nanometer distances and in photosynthesis. but an open question in this area is what effect, if any, the surrounding photonic environment has on this nanoscale energy transfer. by designing and performing a carefully controlled experiment to answer this question, scientists have settled the debate and found clues to improving the efficiency of many of the technologies that rely on this process.

explanation: